SCPT-GS2 GEOTECH NOVA Manual 2018-08-28
2
2 Product Information
General Description
Seismic tests are primarily carried out to measure wave velocities in soil. The SCPT method combines the
shear wave (S wave) speed information from the seismic test with results from the CPTU probe, and will
give you a good basis for evaluation of a number of critical soil properties, e.g. the risk for liquefaction.
The SCPT-GS2 GEOTECH NOVA adapter is equipped with two sets of very sensitive 3-axial seismic sen-
sors that are mounted with a fixed distance from each other (normally 1 meter). Data processing takes
place in the down-hole seismic adapter. The data is transferred to the surface equipment on digital form,
without test results being affected by noise or cable properties. The well-defined distance between sensors
and down-hole analogue/digital conversion gives high accuracy and repeatability.
Please refer to separate literature for detailed information on scientific background and evaluation methods.
GEOTECH NOVA is a modularly designed product family for user-friendly, robust and accurate CPT,
CPTU, Seismic CPT (SCPT), Electric Conductivity CPT and Vane Test soil investigations. This manual
concentrates on seismic features. Please refer to separate documents for descriptions of CPT/CPTU, Elec-
tronic Conductivity CPT and Vane Testing.
The SCPT down-hole assembly typically comprises a CPTU probe and a seismic adapter mounted on a
standard CPT rod. The CPTU probe gives accurate measurements of cone resistance (Qc), sleeve friction
(fs) and pore pressure (u). Options for sintered pore pressure filters in u1 and u2 positions as well as slot
filters are available.
Fig. 1 – The CPT NOVA probes are designed for use on land as well as off shore, and give accurate
measurements of cone resistance (Qc), sleeve friction (fs) and pore pressure (u) (figure shows pore
pressure filter in standard position “u2”). In addition there is a built-in inclinometer.
The seismic wave is normally generated at the ground surface or at subsea applications on the seabed. A
modified sledgehammer and a metallic plate form a simple and reliable wave source for use on land:
